This proposal outlines a co-ordinated laboratory and clinical approach to evaluate the therapeutic efficacy and in vivo immunomodulatory activity of human fibroblast interferon (HFIF) in patients with non-Hodgkin's lymphoma and multiple myeloma. The HFIF produced at RPMI on a large scale is a product of normal diploid human fibroblasts and is highly purified by affinity chromatography on Con A-agarose and phenyl-agarose to a specific activity of over 10 to the seventh ref. units per mg protein. This HFIF preparation has received FDA approval for human use as a result of demonstrated safety and purity. The antitumor effects of HFIF will be assessed in a single arm, Phase II clinical trial in a minimum of 10 patients with non-Hodgkin's lymphoma and 10 patients with multiple myeloma. All patients will be monitored for clinical response and multiple laboratory parameters during a six-week course and 4 months follow-up. Each patient will receive an escalated dose scheduled beginning with 3 x 10 to the sixth units daily and continuing for 6 weeks for a total maximum dose of approximately 200 x 10 to the sixth units. All patients will concomitantly be studied for in vitro immunoregulatory activity, T subset function, various cytotoxic functions including CML, ADCC and NK activity, macrophage function, surface markers and flow cytometry utilizing monoclonal antibodies to lymphocyte subsets. Clinical and laboratory parameters in each patient will be correlated with serum interferon levels to assess the in vivo immunomodulatory effects of HFIF as well as any potential therapeutic benefits.